I have a custom internet access design. Two circuits T1 and 2xT1 to same ISP. The 2xT1 circuit is the primary one in the VRRP group. The T1 is the stand-by connected to CISCO 2801. The ISP claims that I can use the single T1 just for outgoing traffic if I want to, the primary one (2xT1) is used for both directions: outgoing and incoming. The problem is that the T1 circuit doesn't seem to forward traffic. I believe that the router is setup properly because when I fail over to the T1 from 2xT1 the 2801 on T1 works fine. So I wonder how to monitor traffic on the Serial interface and prove to my ISP that 2801 routes traffic to the ISP. This would prompt them to troubleshoot the problem on their end where. I think I could use the debug but would really apreciate if someone gives me some sample commands. I'd like to ping a public IP like 22.214.171.124 from a test host on the subnet for which default gateway is set to Fa interface of 2801 and see the ICMP request on the serial interface by using debug. Of course the circuit works only for outgoing traffic (that's what ISP claims) so at this point nothing is being received back so ping fails but if I see that debug shows ICMP request going through the serial interface, I can give this to my ISP and ask them to fix the circuit.